A facsimile (fax) comprises a document in a digital image format. The document is associated with metadata that specifies a destination with respect to the publicly switched telephone network (PSTN). Thus, typically for at least a portion of the transmission, the document is transmitted over the PSTN. Faxing provides a secure, traceable and non-repudiable mechanism for content delivery and can be particularly useful in business environments.
Faxing, however, has limitations. For example, conventional fax machines can only transmit black and white files with limited resolution in a specific format such as the Tagged Image File Format (TIFF). Further, the transmission speed can be very slow compared to today's Internet based standards. Not surprisingly, the faxing technology in recent years has faced increasing competition from Internet Protocol (IP) network (e.g. Internet, LANs, WANs, intranets, extranets, etc.) based alternatives (generally referred to as Internet faxing). For example, instead of standalone fax machines, fax servers may be utilized in enterprise network environments. Typically, a fax server is a server computer having the necessary fax software and hardware to receive and send faxes over IP networks. Using fax servers may reduce the cost of transmission since there is no telephone connection charge when sending a fax over the Internet.
Internet based alternatives to physical fax machines are not without drawbacks. One challenge is that the Internet carries a vast range of information resources and services over a hodge-podge of protocols. For example, a user may send an email over the Internet, upload a file to a network site, and make a phone call over the Internet. The email may be sent via the Simple Mail Transfer Protocol (SMTP), the file may be uploaded via the File Transfer Protocol (FTP), and the phone call may be conducted using the Voice over IP (VoIP). Many existing network protocols do not meet the secure, traceable and non-repudiable needs of today's businesses. For example, the email (along with any attachment) as well as the file sent over the Internet unencrypted can be vulnerable to interception.
Additionally, network faxing solutions may include the need to access fax modems, routers or the PSTN (e.g. telephone lines) at the user's physical location. Increasingly, however, in most other areas of communication, including telephony itself, the trend has been toward use of the IP network based protocols (e.g. SMTP, FTP, VoIP, etc.). Accordingly, many traditional fax users no longer wish to maintain telephone lines or other access to the PSTN. It would therefore be desirable to give these users the ability to continue sending and receiving faxes without having to maintain local access to the PSTN.